Rama Shankar Yadav

Checkpointing Based Fault Tolerance Patterns for Systems with Arbitrary Deadlines

This paper aims to provide a fault tolerant scheduling algorithm that have fault tolerance patterns for periodic task sets with arbitrary deadlines. The fault tolerance is achieved by checkpointing where number of checkpoint is decided on the bases of the lemmas proposed. These patterns provide minimum tolerance to all the releases and an improved tolerance to some releases pertaining to the availability of the slack time. They may be binary (i.e., either provide maximum or minimum tolerance to a release) or greedy (i.e., provide an improved tolerance whenever it is possible) in nature. Theorems have been proposed to ensure that the task set is schedulable with at least minimum fault tolerance. The effectiveness of the proposed patterns have been measured through extensive examples and simulations.

Enhanced Intercycle Switching in p-Cycle Survivability for WDM Networks

The p-cycle is the most promising technique used for the survivability of WDM networks. Relevant studies conducted by eminent researchers in this field have suggested that the reliability of the p-cycle can be enhanced further. In order to address the problem, the authors introduced a concept, namely, intercycle switching (ICS), that reduces the length of the p-cycle restoration segment by exploiting an idle p-cycle. This reduction implies a minimized restored path (end-to-end) length and thus improves the quality and reliability of optical transport networks. Through this paper, the authors show how the effectiveness of the ICS approach can be enhanced by considering the restored path during intercycle switching instead of the p-cycle restoration segment, namely, as enhanced ICS (EICS). Furthermore, the authors worked on the optimal allocation of the candidate p-cycle and idle p-cycle (OPIA) to the working paths to choose the restored path optimally where EICS is more effective.

Bandwidth Delay Quality Parameter Based Multicast Congestion Control

Computer network is an important phenomenon for digital information world. Computer network having the various problem due to more demand such as congestion control security, reliability, scalability, fairness etc. Multicast service helps computer network to flow information from one end to another end. In this paper, we provide BDQP approach to minimize the congestion control. NS-2 result shows, BDQP congestion control scheme minimizes the congestion and provides better network performance to provide more quality data.

A Utilization Based Approach for Secured Real Time Applications on Clusters

In today arena security critical real time applications running over clusters are growing rapidly. As an application running on clusters demand both timeliness and security, an efficient scheduling algorithm is needed that has better performance in terms of both number of task accepted and security value received.. In this paper the approach focuses on essential parameter i.e. Success ratio for a real time system while guaranteeing minimum security. We have used deferred approach and load balancing to maximize Success ratio. Further, simulation studies have been carried out in MATLAB (module for Real-time) to measure the performance of modified approach

A Preemption Control Technique for System Energy Minimization of Weakly Hard Real-Time Systems

This paper aims to present a general scheduling algorithm which offers lesser energy consumption for weakly hard real time systems modeled with (m, k) constraint. The weakly hard real time system consists of a DVS processor (frequency dependent) and peripheral devices (frequency independent). The energy minimization is done in two phases. In the first phase we suggest new static partitioning strategy that partitions the jobs into mandatory and optional followed by a greedy based speed assignment at the task level. Theorem is being derived to show the feasibility condition of weakly hard real-time system with modified partitioning strategy. The second phase proposes a preemption control technique that can effectively reduce the preemption impact by delaying the higher priority jobs. The simulation results and examples demonstrate that our approach can effectively reduce the overall system energy consumption (especially for systems with higher utilizations) while guaranteeing the (m, k) requirement at the same time.

Efficient ID-Based Multi-proxy Signature Scheme from Bilinear Pairing Based on k-plus Problem

Proxy signatures are efficient alternatives to delegate the signing rights. In a proxy signature scheme, the original signer can delegate its signing rights to any other party, to make signature on its behalf. In a multi-proxy signature scheme, the original signer delegates its signing rights to a group of persons called proxy groups. With the exploit of bilinear pairing over elliptic curves, several ID-based multi-proxy signature schemes have been developed till now [5,9,17]. In this paper, we have proposed an ID-based multi-proxy signature, based on ‘k-plus problem’. The proposed scheme is secure under the INV-CDHP assumption. Moreover, our scheme is computationally more efficient than the schemes [5,9] and assure all the security requirements of a proxy signature, given in [11].

Quality Enhancement in p-Cycles Using Optimized Restoration Path (ORP) Algorithm

We consider extensions of the design theory and related operating concepts to support multiple levels of Quality of Service (QoS) for priority-based traffic in a transport network that uses p-cycles as the basic protection method. The proposed integrated QoS scheme can provide appropriate transport service for various applications relating to different service categories. Notably this includes in the current state-of-the art, a span carrying different priority traffics when get failed, its traffics are routed randomly over the available restored paths. A significant finding is that the allocation of the restored paths to different traffic on the failed span should be done on the priority basis. In this paper, the work shows how to economically support the restoration of failed span on priority basis in the upward quality direction. Through priority considerations, there is reduction in the restored path length for premium-grade traffic, thereby decreasing the propagation delay, excessive signal degradation and increases the reliability of the restored path in the event of second failure.

Partitioning-based approach to control the restored path length in p-cycle-based survivable optical networks

In recent years, p-cycles have been widely investigated for survivability of WDM networks. They provide fast recovery speed such as ring and capacity efficiency as mesh survivability schemes. However, restoration paths are very long, which causes excessive latency and intolerable physical impairments. On the other hand, nowadays, a wide set of applications require an optical path with almost no delay. The existing approaches, namely loopbacks removal and inter-cycle switching, provide a significant reduction in the restored path, but even then a number of restored paths remain many times longer than the working path lengths. In this paper, we propose a network partitioning-based approach to control the length of each restored path as per delay sustainability of time critical applications. The basic idea of the work is to partition the network into domains and construct the p-cycles for each domain independently. The domain wise construction of p-cycles restricts their length, which consequently reduces the length of restored paths. Here, we introduce a new concept where the selected border nodes are overlapped among adjacent domains to cover inter-domain spans of the network as a domain span in order to ensure their survivability through domain p-cycles. Simulation results show that the proposed solution is good enough to control the restored path length with small augmentation in redundancy of spare capacity as compared to optimal design of p-cycles. More importantly, it enhances the dual failure restorability significantly.

Intercycle switching (ICS)-based dynamic reconfiguration of p-cycle for dual-failure survivability of WDM networks

Today, the most promising technique used for the survivability of optical transport networks is p-cycle. However, it provides longer restoration path at failure state of the network. The intercycle switching (ICS) is one of the recent approaches that is based on idle p-cycles and is used for shortening the length of restoration path in single-fault model. Utilization of idle p-cycles degrades the inherent dual-failure restorability of single-failure design model of p-cycle, whereas ICS releases the maximum portion of conventional restoration path by utilizing a small segment of the idle p-cycle. Here, the authors proposed a new approach to reconfiguring the released portion of restoration path and unused segment of corresponding idle p-cycle as new cycle(s). In respect of idle p-cycles, the new reconfigured cycle(s) provides more dual-failure restorability in single-failure design of p-cycle. Therefore, the proposed approach mitigates the above-said drawback of ICS and minimizes additional spare capacity requirement for dual-failure survivability.

An ID-based signature scheme from bilinear pairing based on k-plus problem

An ID-based cryptosystem enables the user to use public keys without exchanging public key certificates. In this scheme, users can use their identity to generate their public and private keys. The notion of bilinear pairing makes the system easy and efficient providing specific securities. In this paper, we have proposed an ID-based signature scheme from bilinear pairing based on k-plus problem. We show that the proposed scheme is existential unforgeable in the random oracle model under the inverse CDHP assumption. Our scheme is computationally more efficient than other existing schemes.